Slalom simulator having rope actuated switch



ug- 25, 1970 B. B. FAGAN 3,525,989

SLALOM SIMULATOR HAVING ROPE ACTUATED SWITCH Filed June 27, 1968 4 Sheets-Sheet 1 @me :516i

INVENT OR BURTON B. PAGAN ATTORNEYS Aug- 25, 1970 B. B. PAGAN 3,525,989

SLALOM SIMULATOR HAVING ROPE ACTUATED SWITCH Filed June 27, 1968 4 Sheets-Sheetl 2 33 @I 44 36 3l 27 37 43 lull- M 46j L17 29 nas ,f

0 INVENTOR BURTON B. PAGAN BY 7?@ #MW ATTORNEYS Llg'. 25, 1970 B, Bh PAGAN 3,525,989

SLALOM SIMULATOR HAVING ROPE ACTUATED SWITCH Filed June 2'?, 1968 4 Sheets-Sheet 5 Y= ROPE LENGTH cou'RsE cEmERLmE 54 49 17 49 /l\ )V l llll I J B6 81j 'I9 84) J '16J ENI-OR BURTON B. PAGAN BY M, a .LM

ATTORNEYS 'rms 60 Aug- 25, 1970 B. B. PAGAN 3,525,989

SLALOM SIMULATOR HAVING ROPE ACTUATED SWITCH Filed June 27, 1968 4 Sheets-Sheet 4 nmz 9"?4# 98 97 99 I 97 (i5 L\\L z\\ WN 11s 116 :n2 |11 Joa 107 img img-"Z" 117 105 /r- Oi 1 i 102 Im-Il na m3 /E 32` D PIGJ4 C\` 106 B 111 A 3.4. w, l 108 |07 w ww m* U4 H33?) n4 H6 I INVENTOR BURTON @PAGQN v ATTORNEYS United States Patent ABSTRACT F THE DISCLOSURE A slalom simulator provides means for practicing slalom runs on water skis without requiring positioning buoys to establish a slalom course. The Simulator provides means for measuring the angle between a ski tow rope, extending between a skier and the tow boat, and the centerline of the slalom course. When the skier has deviated from the course centerline by a distance sufficient for the skier to pass around a buoy, if one were present, the simulator activates an alarm indicating obtainment of the required deviation.

The present invention relates to slalom simulators and, more particularly, to apparatus for providing successive indications to a Water skier that he has deviated a sufficient distance from the centerline of a simulated slalom course to pass around the marker buoys normally employed to define a slalom course for water skiing.

In the United States, the American Water Ski Association establishes all standards for official water skiing events. The present invention, as indicated above, relates particularly to slalom events, and referring to FIG. 1 of the accompanying drawings, there is illustrated an official six-buoy slalom course. The six buoys are located alternately on opposite sides of the centerline of the course, each buoy being spaced twelve and one-half yards from the course centerline; the buoys being spaced fortyve yards downstream from one another. The course is entere-d through an entrance gate consisting of two buoys disposed symmetrically on opposite sides of the course centerline three yards apart. The entrance gate is located thirty yards upstream from the first buoy of the course, and an exit gate is similarly located downstream with respect to the last buoy and the centerline of the course.

The association also prescribes the rules concerning the time of the run, or more particularly, the speed of the boat in traversing the course, as well as the length of tow line to be employed for each run. The tow line has a maximum length of seventy feet, and initially four runs are prescribed at thirty, thirty-two, thirty-four and thirty-six miles per hour with the seventy foot tow line. The rules set forth herein are for boys and men. Similar rules apply to other classes. A second run is conducted at thirty-six miles per hour with a fifty-seven foot tow line. A third run is conducted at thirty-six miles per hour with a fifty-one foot tow line, and again at thirty-six miles per hour with a forty-five foot tow line.

The official course is quite difiicult to establish accurately. It involves a considerable amount of equipment and entails an equally considerable amount of maintenance. The buoys and gates must be accurately located to provide the skier with a true feel for the official tournament course, and the buoys must be maintained.

ice

The present invention is intended to provide the individual water skier or small groups of water skiers who do not have sufficient funds or time to establish and maintain an official slalom course, with the ability to practice for the improvement of their skill, as well as for tournament competition, without having to establish an ofiicial slalom course.

The tow rope which pulls the skier through the water is generally attached to the boat by one of two means. In the more common scheme, ropes known as transom ropes are attached to each side of the transom and brought together at a common point on the centerline of the boat at some distance aft of the transom. This common point is called herein the tow rope attachment point.

A more sophisticated attachment scheme employs a vertical pylon on the centerline of the boat thus providing a single point for bringing the load from the tow line into the boat.

Slalom simulators are a series of devices which provide the means to measure and indicate deviations of a skier from the track of a straight running variable speed tow boat which correspond to the positions of buoys on a slalom course and make possible time measurements corresponding to the timing of an official slalom run.

The slalom simulator of the invention actually determines the angle (the buoy angle) between the tow rope and the centerline of the course and provides some type of indication when a prescribed angle has been equalled or exceeded. The buoy angle for a given length of tow rope is a constant for all courses since the buoys are always located at the same distance from the course centerline. Thus, the length of two sides of a triangle, the tow rope and the perpendicular from course center to buoy are defined and, in consequence, all sides and angles of the triangle are fully defined.

The various devices of this invention relate to the measurement of these angles and the conversion of the measurement to signals for the direct use, in various ways, of the skier and for timing his progress along a simulated course.

Slalom simulators of the present invention which depend for the measurement capability upon the geometry and length of the transom ropes are referred to herein as slack-type simulators.

Slalom simulators of the invention which depend for the measurement capability on a direct measurement of the angle between the tow rope and a line bisecting the angle between two transom ropes are referred to herein as plate-type simulators.

Slalom simulators of the invention which are used with pylon equipped boats and which measure the buoy angle are referred to herein as pylon-type simulators. Pylon-A type simulators can be either of series or parallel configuration, depending upon whether the force of towing the skier is carried through the simulator (series type) or around the simulator (parallel type).

The slalom simulators of the invention are located at the transom rope attachment point, on the transom ropes or on the pylon of the tow boat and are provided with buoy angle sensing means of one form or another to indicate to a skier when he has deviated from the centerline of a course sufficiently to have cleared a buoy of the official course.

In operation, the boat which is towing the skier establishes one of the speeds required by the oiicial rules, and

the water skier passes across the centerline of the course behind the boat on his way toward clearing the tirst simulated =buoy. As he crosses the centerline of the boat, an observer in the boat starts a stop watch which is stopped after the skier has completed vsin deviations to each side of the boat in alternation from one side to the other and then returned across the centerline of the boat. Each deviation which is suicient to clear a buoy produces a visual, audible or tactile signal, and the total course elapsed time is indicative of whether the skier has completed the course within the official time limit; specifically that time which is equal to the time that would be required by a skier to have gone through the entrance gate, around the six buoys, and through the exit gate (if such had existed), at the particular speed at which the boat is proceeding through the course. For instance, if the boat is traveling at thirty miles per hour down the course illustrated in FIG. l, the skier should then complete the course in 19.4 .Seconds, this being based on a total course distance along the path of the boat of two hundred eighty-five yards.

One of the apparatus of the present invention, the platetype simulator, generally comprises an isosceles triangular shaped plate having a pintle pivoted adjacent to the vertex of the equal sides of the device, the skiers tow rope being attached to the pintle. The apparatus is secured to the boat by two ropes extending between two points adjacent to the other two vertices of the plate, and to two hooks or eyes secured to the transom or hull of the boat. In one embodiment of the invention, an apparatus is provided for detecting the angle of the pintle relative to the centerline of the plate. When the skier has deviated from the centerline of the course the proper distance, there is dened a specific buoy angle for the particular length of tow rope being employed and this buoy angle may be measured. When the proper buoy angle is obtained, a circuit is closed and a visual, audible or tactile alarm is activated, This signal simulates to the skier the rounding of a buoy and indicates that he should cross the track of the boat to round the next buoy on the other side of the boat track.

Similarly, when the skier deviates suiiciently to pass around a buoy on the other side of the centerline of the course, the visual, audible or tactile alarm is again activated, directing the skier to another track crossing. The individual in the boat may observe the signals, and when the skier has activated six alarms when proceeding along a course such as in FIG. 1 and recrossed the boat track, he may record the time required for the skier to have eiected six indications, therefore determining whether the skier is actually completing the course in the prescribed time.

Various types of mechanisms for indicating the buoy angle may |be employed. For instance, in one embodiment of the plate-type simulator of the invention, a switch contact is carried on the inner end of the pintle, and stationary switch contacts are located at the proper angle or displacement from the centerline of the plate, such that when the skier has deviated at the proper angle, the movable contact on the pintle contacts one of the stationary contacts.

In another embodiment of the plate-type simulator, cams of various shapes may be made part of the pintle so that a circuit is closed by the operation of the cam at each deviation of the pintle to the appropriate buoy angle on each side of the centerline of the boat.

In another embodiment of the invention, use is made of the fact that, if the length of the two ropes from the transom to the transom rope attachment point are properly selected, when the skier has deviated a proper distance from the centerline of the course, then one of the two ropes vbecomes slack (this phenomenon to be described subsequently in greater detail). Tension switches connected in parallel are located on both of the transom ropes, and initially, when the skier begins to proceed down the course, the tensioning on the rope opens both of the switches. However, when the skier has deviated to the buoy angle, one of the ropes becomes slack, the tension switch closes andthe appropriate indication is provided.

Tension switches can be incorporated as part of the hooks which are used to attach the transom ropes to the hull of the boat.

Still another aspect of the invention relates to operation of the device with different lengths of tow line. Intuitively, it can be seen that as tow line shortens, the angular deviation or buoy angle required of the skier becomes greater. Specically, if the skier is trailing the boat by seventy feet, he must deviate twelve and one-half yards from the centerline of the course, the angle between the tow line and the centerline of the course, is less than if a forty-live foot line is employed.

For both the plate-type simulator and the slack type simulator, the transom rope length must be varied as the length of the tow rope is varied such that the included angle between the transom ropes at the transom rope attachment point is equal to twice the buoy angle.

The points of attachment of the transom rope to the plate-type simulator must be varied such that the included angle between the points of attachment and the pintle pivot is equal to twice the buoy angle.

It is an object of the present invention to provide a slalom simulator permitting a water skier, in the absence of an actual slalom course layout, to practice slalom skiing and permit a determination of proper execution of the course with different lengths of tow line and different boat speeds as prescribed in the oical rules.

It is another object ot the present invention to provide a slalom simulator for water skiing which is readily adaptable to different lengths of tow line so that all of various prescribed slalom events may be practiced by using a single simulator.

Still another object of the present invention relates to a slalom simulator for water skiing which measures the angle between a skiers tow rope and the centerline of a slalom course and provides an indication whenever the skier has deviated from the course centerline by a prescribed distance.

The above and still further objects, features and advantages of the present invention will become apparent upon consideration of the following detailed description of several embodiments thereof, especially when taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a diagrammatic view of a slalom course for water skiing;

FIG. 2 is a top view of one embodiment of the apparatus of the present invention;

FIG. 3 is a diagrammatic illustration of the apparatus of FIG. 2 under a specific condition during use for its intended purpose;

FIG. 4 is a side view partially in section of a tension sensing switch which may be employed in place of the switch assembly incorporated in the apparatus of FIG. 2;

FIG. 5 illustrates the manner of use of the tension sensing switch of FIG. 4;

FIG. 6 is a top view of another embodiment of the present invention;

FIG. 7 is a side view in elevation of the rope attachment device employed in FIG. 6;

FIGS. 8-10 are diagrammatic view of the angular relationships involved in determining locations of various rope attachment positions of the device of FIG. 6;

FIG. 11 is a side view in elevation of the apparatus of FIG. 6;

FIG. l2 is a side view in elevation of a slack-type simulator incorporated in fitting which attaches transom ropes to boat structure;

FIG. 13 is a side view in elevation showing the pylon slalom simulator of the parallel type; and

FIG. 14 is a top plan view of a pylon slalom simulator of the parallel type.

Referring now specifically to FIG. 2 of the accompanying drawings, there is illustrated a plate type slalom simulator generally designated by the reference numeral 1 comprising a generally isosceles triangular plate having two equal length sides 2 and 3. The plate is provided with a pivot 4 for a pintle 6 adapted to receive a tow line 7. The plate 1 is apertured at 8 and 9 adjacent the vertices opposite the location of the pivot 4, apertures 8 and 9 being adapted to receive ropes 11 and 12, respectively, which are secured to appropriate anchoring mechanisms or eyes on the transom of the tow boat.

The pintle 6 is provided with a longitudinally extending arm 13 directed away from the end of the pintle adapted to receive the tow rope. Two insulating contact supporting blocks 14 and 16 are disposed respectively on the right and left sides, as illustrated in FIG. 2, of the plate 1 in the path of movement of a contact 17 carried on the end of the arm 13.

When the pintle 6 is rotated through a predetermined angle, the contact 17 engages appropriate contact members 18 or 19 secured to the blocks 14 and 16. The coittacts 18 and 19 are connected to a common return `wire 21 and the contact is electrically connected via arm 13, pintle 6 and pivot 4 to the plate 1; the plate 1 being connected to a ground or return wire 22. Thus, the leads 21 and 22 are electrically connected to one another whenever the contact 17 engages one of the contacts 18 or 19.

The slalom simulator illustrated in FIG. 2 is designed for a specific length of tow rope, for instance, a seventy foot rope. If the included angle 9-4-8 and the length of ropes 11 and 12 are properly selected for a seventyfoot tow rope, the apparatus does not require stops for the pintle 6 to prevent damage to the arm and contact mechanism 13 and 17. To more fully explain this feature of the present invention, reference is made to FIG. 3 of the accompanying drawings. In FIG. 3, it is assumed that the tow line 7 is seventy feet long and that the skier has deviated from the centerline of the course by the prescribed distance to clear a buoy which is designated by reference numeral 23. When the deviation is as illustrated in FIG. 3, the tow line 7, pintle 4 and the rope 11 lie along a common straight line and the contact 17 engages the contact 18. Further deviation of the skier away from the centerline of the course or to the left as illustrated in FIG. 3 maintains exact alignment between the elements 4, 7 and 11 while the line 12 becomes slack. Thus, no further movement of the arm 13 relative to the block 14 can occur and thus no damage is sustained by the contact mechanims. The phenomena of one of the transom ropes becoming slack when the angle which the tow rope makes with the track of the boat is slightly greater than one-half the included angle between the transom ropes may be employed to provide a different type of sensing mechanism for proper deviation of the skier. This is known as the slack-type simulator. Specically, since one of the ropes 11, 12 becomes slack when the skier has deviated from the course centerline by the prescribed distance, tension sensing mechanism may be employed for making the determination of appropriate deviation of the skier.

Referring now specifically to FIG. 4 of the accompanying drawings, there is illustrated a type of tension sensing switch which may be employed for sensing the tension in the ropes 11 and 12 of FIGS. 2 and 3. The device comprises a generally cylindrical body 26 having a bolt 27 extending through one end thereof. The bolt is held in place by two nuts 28 and 29 which engage the left end 31 of the hollow cylindrical device 26 but are electrically insulated therefrom by means of fibrous insulating washers. Electrical lead 32 and a metal ring 33 are disposed about the bolt 27 outwardly of the hollow cylinder member 26 and held thereon by means of a nut 34 and appropriate washers. The ring 33 is secured to a rope or more properly a string 36 in a well known manner.

The bolt 27 extends a predetermined distance into the hollow cylindrical member 26 where it is normally 6 abutted by a plate 37. The plate 37 is biased toward the bolt 27 by means of a relatively heavy compression spring 38 which extends between the shoulder 39` on the plate 37 and right end 41 of the hollow cylindrical member. The plate 37 is litted with a nut and a bolt arrangement as generally designated by reference numeral 42 which is used to secure a wire 43 and a rope 44 to the plate 37.

In order to provide for instance an audible alarm, the electrical leads 32 and 43 are returned to the boat and are connected in series with a circuit comprising a battery 46 or other suitable source of electrical energy and an enunciator 47 which is illustrated as a horn. Of course, the horn can be replaced by any other audible alarm or for that matter, visual or tactile alarm.

In operation, the ropes 11 and 12 are made slack or a one-inch loop may be put in the rope and the strings 36 and 44 are tied across the loop somewhat similarly to the arrangement illustrated in FIG. 5 of the accompanying drawings. It is apparent that, so long as the rope is slack as illustrated in FIG. 5, the compression spring 38 of FIG. 4 maintains the plate member 37 in contact with the bolt 27. However, when tension due to the towing of the skier is applied to the rope 11, the plate 37 is pulled away from the bolt 27 against the force of the compression spring 38, opening the circuit between wires 32 and 43.

Returning now to FIG. 3 of the accompanying drawings, it can be seen that when a water skier is being towed and is along the centerline or close to the centerline of the course both of the ropes 11 and 12 are in tension and the electrical circuit illustrated in FIG. 4 is open due to disengagement of the member 37 from the bolt 27 on both tension switches. However, when the skier has deviated sufliciently to clear a buoy as illustrated in FIG. 3, the line 11 becomes slack, the compression spring closes the plate against the bolt 27 and the alarm is sounded. Two devices of the type illustrated in FIG. 4 are Iequired, one being secured to each rope. Electrically, the devices are wired in parallel, see switch 40 of FIG. 4, so that the alarm is sounded if either switch is closed. Also a switch 45 may be employed to open the alarm circuit when not in use.

As previously indicated, the apparatus in the form illustrated in FIG. 2 is useful with one particular length of rope or tow line. When a different length of tow line is employed improper indications would be given if the device were not altered since the angles to be sensed change.

Reference is now made to FIG. 6 of the accompanying drawings wherein is illustrated an apparatus that may be employed with each of the various prescribed lengths of tow rope and provide a proper indication for each such length of rope. The apparatus which is generally designated by reference numeral 48 again comprises a pair of spaced, parallel, generally triangular plates 49 and 76 having a pintle 51 pivoted about a pivot 52 adjacent one of the vertices of each of the members 49 and 76. 'Ihe bases of the plates opposite the aforesaid pivot point are provided with five groups 50 of two holes each with the holes of each group disposed on opposite sides of the centerline of the plate by equal distances. Each hole is adapted to receive a pin 53 which extends through ears formed on the two ends of a generally U-shaped member 54. This arrangement is more clearly illustrated in FIG. 7. The pin is provided with an aperture opposite the head end thereof to receive a cotter pin 56 for locking the pin in place. One end of rope is adapted to pass around the base of the member 54 and the other end is secured to the transom of the boat.

Each pair of holes 50 is to be employed with a tow rope of a prescribed length. As previously indicated in the introduction of this application, the prescribed lengths of rope for men and lboys are forty-live, fifty-one, fifty-seven, sixty-three and seventy feet. When a tow rope of one of these lengths is employed, the pin and rope holder arrangements 53 and 54 are attached to the plate 49 at the locations indicated by the specific rope length being employed. The location of the various holes in which the members 54 are to be secured may be determined by use of triangulation as illustrated in FIG. 8 of the accompanying drawings. Each buoy is located twelve and onehalf yards from the centerline of the course.

In FIG. 8, the centerline of the course is designated by the reference numeral 57. A ibuoy is indicated by reference numeral 58 and the pivot point of the pintle 51 is designated by the reference numeral S2 as in FIG.l 6. The rope length is designated by the letter Y and the angle between the tow rope Y and the centerline 57 is desigf nated by qb. In the table below, the angle rp and the sine of the angle gb are listed for each length of the tow rope.

TABLE I Y=rpe length Sin Q5 If the angle qb for each length of two rope is laid out on the plate 49 with the pivot 52 at the vertex and the centerline of plate 49 as the reference leg of the angle, each of the lines designating the outer leg of an angle intersects a baseline S9 on the plate 49 at the location of each of the holes for the specific length of tow rope. Actually, two angles are laid out for each value of qb, an angle for each side of the centerline so as to indicate the location of each hole 50 to each pair of holes.

The length of the ropes extending between the plate 49 and the transom of the boat must be changed for each length of tow rope if one of the ropes is to become slack when proper deviation is achieved.

The length of the transom ropes can readily be determined frorn FIG. 9 of the accompanying drawing which illustrates the location of the boats transom, more particularly an anchor point on the boats transom, and the location of the plate 49 of the simulator of the present invention with different length tow ropes, relative to a buoy of a iixed distance from the course centerline. Specifically, a buoy which is designated by the reference numeral 60 is at a fixed location along a course. Lines 61, 62 and 63 represent tow lines of lengths, for instance fortyfive, fifty-seven and seventy feet respectively. The centerline of the simulator 49 must remain along the centerline of the course and the anchor point on the transom of the boat also remains at a constant distance from the centerline of the course, since the two anchor pins on the transom are maintained at a fixed location relative to the centerline of the boat and thus the course. One of these latter points, that is the anchor points on the transom of the boat is indicated by the reference numeral 64. lt can be seen from the drawing of FIG. 9 that the angle of the tow line with the centerline of the device changes with each length of line and that the length of the rope between the anchor 64 on the transom of the boat and the plate 49 increases as the length of the tow line increases. Further, also the point at which the extension of the tow lines crosses the base line 5,9 of the member 49 becomes closer to the centerline of the plate 49 as the length of the tow line increases.

The actual length of rope between the transom anchor 64 and the pintle pivot 52 may be calculated as follows: if the distance between anchor points I64 and 64 on the transom of the boat (see FIG. l0) is taken as a length B and Z represents the length of line between one of the points 64 and 64 and the pivot point 52 of the plate 49, then:

B is a Xed distance for any particular tow boat and thus Z can be determined by substituting the values of sin qs in the equation from Table I, these values being indicated in Table II below.

TABLE Il Rope length Sin S=X Z 32. 4 .535 l. 87- BIZ 36. 5 595 l. 67- B/2 41. l .658 l 52-B/2 47. 2 735 l 36B/2 56. 5 .834 l. 28B/2 Referring now specilically to FIGS. 6 and ll, since the angle that the pintle 51 makes with the centerline of the apparatus for a speciiic deviation of the skier; that is, the deviation required to clear a buoy (buoy angle), changes with the length of the tow line, the mechanism for sensing deflection of the pintle, or more particularly, the angle of rotation of the pintle relative to the centerline of the device, must also take into account this difference. lIn FIG. 6, a second set of groups of four holes 67, 68, 69, and 71 and 72. is provided, the inner two holes of each group, each lying along a line drawn from the center of one of the holes 50 to the pivot point 52 of the pintle 51. For instance, a line 73 drawn from the center of the hole 50 for the seventy foot tow line and the center of the pivot 52 for the pintle intersects the center of one of the holes 67. A line drawn from the hole on the opposite side of the centerline for the seventy foot tow line to the center of the pivot 52 intersects the center of the second one of the holes 67. These holes and the two further holes of the group designated 67; also dispose symmetrically on opposite sides of the centerline of the plate 49 are adapted to receive pins from a switch sensing mechanism illustrated in elevation in FIG. ll.

The switch apparatus of FIG. ll comprises a pair of spaced, dat, parallel plates 74 and 82, secured to the member 49 by a plurality of pins, generally designated by the reference numeral 77, when seated in appropriate sets of holes 67, 68, `69, 71 and 72 and their primes. Secured to the top of the number 74 is a exible reed or member 78. Bolts 79 having their heads seated in the plate 74 extend upward through reed 78, a rigid insulating and spacing block 81 and contact plate 82. Nuts or similar securing devices 83 are applied to the end of the bolts 79 to rigidly secure the assembly to the plate 74 and thus to the plate 49. The reed 78 carries two members 84 and 86 which extend downwardly through apertures in the plates 49 and 74 and into the region between the plates 49 and 76. lA tongue 87 extends from the pintle 51 of FIG. 6 toward the base lines S9 of plates 49 and 76. The height of tongue 87 is less than the height of the region between the plates 49 and 76.

The member 87 is beveled and upon rotation through a predetermined distance with rotation of the pintle 51 one of the sloping surfaces on member 87 engages a corresponding sloping surface on the bottom of one of the members 84 and 86. Continued rotation of pintle 51 about the pivot point 52 causes, for instance, the member 86 or the member 84 to raise and deect one end of the ilexible member 78. When the pintle 5,1 has been deflected through an appropriate angle, one of two contacts 88 and 88', carried near the opposite ends of reed 78, is raised sufficiently to engage a contact 89 or 89" respectively disposed immediately thereabove and secured to the underside of the plate 82.

By locating the mechanism of FIG. ll at the appropriate holes 67 through 72, engagement between the contacts 88 and 89 or 88 and 89 is produced whenever the skier has moved outwardly from the centerline of the course through the buoy angle. Appropriate electrical wiring may be provided, as generally indicated in FIG. 4, to

produce an audible, visual or tactile alarm Whenever engagement is produced between contacts of the mechanism of FIG. 1l.

Another form of slack-type simulator can be configured as shown in FIG. 12. This device is substituted for the hook or fitting which attaches the transom ropes to the hull or structure of the boat.

Referring to PIG. 12, it is seen that a loop of the transom rope 12 is passed around the hook 91 and rests against pressure plate 92. When rope 12 is in tension, pressure plate 92 is forced to the right as viewed in F-IG. 12 against hook 91. This pressure, transferred through rod 94 and washer 93 secured thereto compressesfspring 95. At the same time, rod 94 separates contact bar 96 carried near the end of rod 94 from stationary contact 97, opening the circuit connected thereto. i

Wires 98 and 99 are connected to contacts 97 and are connected in parallel with wires from theA corresponding apparatus at the other connection point to perate the signal in a manner similar to that shown for the tension switch in FIG. 4.

When either of the transom ropes becomes slack, the spring 95 presses against washer 93 and moves rod 94 to the left, bringing contact bar 96 in contact with contacts 97. The circuit between wires 98 and 99 is closed, indicating that the tow rope has assumed the angle at which the skier would pass around the buoy on an 'oicial course.

Similar slack-type simulator switches may be conrfigured for various means of attaching the transom ropes to the hull.

A pylon-type simulator may be configured by rigidly aixing a plate-type simulator such as shown in FIG. 6 to the pylon so that the centerline of the plate CL-CL corresponds to the centerline of the tow boat.

The tow rope can then be attachedd to the pintle of the simulator and excursions of the skier simulating buoy roundings on each side of the boat will then be indicated by circuit closings as described for the plate-type simulator. This configuration is called the series-type pylon simulator. However, attaching the tow rope to the pintle pylon be able to resist strong twisting forces. To eliminate these twisting forces, the tow rope may be attached directly to the pylon with the plate simulator mounted rigidly on the pylon so that its pivot is directly above the pylon. The pintle is then attached to the tow rope by means of a light line and spring. This scheme, named the parallel pylon sirnultaor, greatly reduces the twisting forces which must be resisted by the connection between the pylon and the plate is illustrated in FIGS. 13 and 14 of the accompanying drawings.

Referring specifically to FIG. 13 which illustrates a conventional pylon arrangement with the simulator of the invention attached, a tow rope 101 is normally connected to an attachment eye which pivots about the vertical axis of a pylon 103. The pylon-type slalom simulator 104 includes a cam 106 attached to the tow rope 101 by means of a string 107 and a light spring 108'. As the skier moves from side to side of the 4boat track, the tow rope attachment eye 102 pivots about a spacer 109 and bolt 111 and the string 1013, spring 104 assembly causes the cam 106 to pivot about the bolt 111. The cam is therefore rotated about the boat axis in synchronism with the movements of the tow rope.

A switch positioning plate 112 is held rigidly to the pylon 103 by the bolt 111 so that the centerline of the switch positioning plate 112 remains aligned with the fore and aft axis of the boat.

The cam 106 has an axisymmetric gull-wing shaped cam surface 113 generated such that when the cam 1016 is rotated by an angle equal to the buoy angle for a particular tow line length, a point on the cai'n operating surface 113 is coincident with the center of that one of a plurality of threaded switch location holes 114 formed in plate 112 which corresponds to a prescribed length of tow line.

A sealed, cam-operated switch 116 is screwed into a threaded switch location hole 114 in plate 112 corresponding to the length of the tow line used. The switch 116 has a downwardly depending conical rod actuator 117 which is engaged and pushed upward by the cam operating surface 113 of cam '106i when the cam has rotated to the buoy angle, closing the switch and thus a circuit between wires 118 and 119 and operating indicators as described previously.

A support plate 121 is for structural rigidity and plays no active part in the operation of the device.

Under certain circumstances, an audible or visual signal to the skier might prove unsatisfactory or difcult to use. Another embodiment of the invention is a tactile signal to the skier that he has reachedthe buoy angle.

A two conductor wire is woven in the center of the tow rope and carried tothe handle. The handle used is fitted with a hollow cylindrical center. Into this hollow handle center is fitted afi electrical device, which when energized through the conductors in the tow rope, produces a distinctive vibration in the handle. Either a solenoid with a reciprocating core or a small motor with an eccentric ywheel will produce this vibration in the handle which is easily sensed by the skier.

The nature of the slalom course, consisting of two gate passages and six buoy rroundings, lends itself to automatically timing of the run.

While I have described and illustrated several embodiments of my invention, it will be clear that variations of the details of `construction which are specifically illustrated and described may be resorted to without departing from the true spirit and scope of the invention as deiined in the appended claims.

I claim:

1. A slalom simulator for determining when a water skier, being pulled through the water by a tow line attached to a boat, has deviated from the path of the boat by a distance at least equal to the standard displacement of the slalom buoy from the centerline of a slalom course, and of notifying the skier and/ or an observer of this deviation by audible, visible or tactile means said simulator comprising an electric switch, a movable element for varying conductivity through said electric switch upon movement of said movable element, means for coupling said movable element to the tow line pulling the skier so as to position said element to establish a predetermined condition of conductivity through said switch when the angular deviation of the rope from the path of the boat is less than a prescribed angle, and to alter the position of said movable element to change the condition of conductivity through said switch when the angular deviation of the tow rope from the path of the boat is at least as great as said prescribed angle.`

2. The combination according to claim 1 wherein said means for coupling comprises a plate having a pintle pivotally secured thereto, said tow rope adapted to be secured to said pintle, means for securing the end of said plate opposite said pintle to said boat, said movable element being secured to said pintle for rotation therewith.

3. The combination according to claim 2 wherein means for securing comprises a pair of lengths of material extending from said plate to said boat, an extension of the longitudinal axis of each of said lengths of material passing through the pivot point of said pintle and forming with the path of said boat said prescribed angle, said lengths of material forming angles of opposite sense with the path of said boat.

4. The combination according to claim 2 further comprising a pair of stationary electrical contacts secured to said plate, a further electrical contact secured to said movable element, said stationary contacts being aligned on opposite sides of said movable contacts in the path of movement thereof.

5. The combination according to claim 3 wherein said plate is provided with a plurality of pairs of holes for attaching said lengths of material to said plate, the holes of each pair being disposed on opposite sides of and equal distances from the centerline of said plate which passes through the pivot point of said pintle, means cooperating with said holes for securing said lengths of material :to said plate, each pair of holes being located such that lengths of material, when secured to said plate via said holes, make an angle with the centerline of the slalom course equal to the prescribed angle for a predetermined length of tow rope.

6. The combination according to claim further comprising means for establishing different positions of said electric switch relative to said movable element so that said condition of conductivity is altered upon said tow rope obtaining different predetermined angles as a function of the length of said tow rope.

7. The combination according to claim 6 wherein said means for establishing establishes positions of said switch such that said switch conductivity is altered when said movable element has been deflected through an angle the sine of which is X/ Y where X is the standard distance of a slalom buoy from the centerline of a slalom course and Y is the length of the tow rope.

8. The combination according to claim 1 wherein said means for coupling comprises a plate having a pintle pivotally secured thereto for receiving said tow rope, a pair of lengths of material extending from said plate to said boat, an extension of the longitudinal axis of each said length of material passing through the pivot point of said pintle and forming with the path of said boat said/ prescribed angle, said lengths of material forming angles of opposite senses with the path of the boat, a second switch having a movable element, said means for coupling further comprising means for securing each said switch to a different one of said lengths of material such that each said movable member alters conductivity of its associated switch upon a change of its associated length of material between taut and slack conditions.

9. The combination according to claim 1 further comprising a pair of lengths of material extending from said boat at equal transverse distances from the centerline of said boat, said means for coupling securing said lengths of material to one end of the tow rope, the angle between each said length of material and the path of the boat being equal to said predetermined angle, means securing said electric switch to one of said lengths of material such that said movable member is moved as a function of tension in said length of material to alter the conductivity of said switch.

10. The combination according to claim -1 further comprising a support member, a plate pivotally secured to said member, said plate having a cam surface, means for coupling said plate to said tow rope, means for mounting said support member so that the pivot for said plate and the pivot point for the tow rope are coaxial, and means for securing said electric switch to said support member such that said movable member is operated by said cam surface.

11. The combination according to claim 3 wherein said plate is provided with a plurality of pairs of attachment means for attaching said lengths of material to said plate, the attachment means of each pair being disposed on opposite sides of and equal distances from the centerline of said plate which passes through the pivot point of said pintle, means cooperating with said attachment means for securing said lengths of material to said plate, each pair of attachment means being located such that lengths of material, when secured to said plate via said attachment means, makes an angle with the centerline of the slalom course equal to the prescribed angle for a predetermined length of tow rope.

References Cited UNITED STATES PATENTS 2,682,042 6/ 1954 Harcum 340-407 X HAROLD I. PITTS, Primary Examiner U.S. Cl. X.R. 

